Floating Seal Gasket for Sanitary Gate Valve
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Solution Overview
Problem
Gate valves used in high-purity industries like food processing and pharmaceuticals face challenges in meeting sanitary requirements due to the need for frequent cleaning of gaskets, which often requires manual intervention and can lead to contamination and degradation of rubber gaskets under harsh cleaning conditions.
Innovation Solution
A valve stem-plug and seal assembly featuring a floating seal gasket with an annular ring design, providing a double-contact seal and a leakage chamber for detection, actuated by a single plug, allowing for cleaning-in-place (CIP) without dismantling and using PFA or similar materials that resist degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rubber gaskets are used for sealing, then sealing capability is improved, but the gaskets degrade and crack after repeated exposure to harsh cleaning conditions
Solution Approach 1:
The patent changes the material parameter from rubber to PFA (perfluoroalkoxy), a fluoropolymer that maintains its mechanical and chemical properties after repeated exposure to harsh cleaning conditions. This material substitution resolves the contradiction by providing both reliable sealing capability and extended service life under aggressive cleaning environments.
Solution Approach 2:
The patent employs PFA, a fluoropolymer composite material, which combines the benefits of chemical resistance, mechanical durability, and sealing effectiveness. This composite material approach allows the gasket to withstand harsh cleaning solutions without degradation while maintaining its sealing function.
2Object-affected harmful factors
If gaskets are detached and completely removed for cleaning, then cleaning effectiveness is improved, but the process requires manual intervention and stops production
Solution Approach 1:
The patent enables the gasket to be cleaned in-place without removal from the valve assembly. The self-service cleaning capability allows cleaning solutions to flow through the valve body and contact the gasket directly, maintaining both cleaning effectiveness and production continuity by eliminating manual disassembly and reassembly operations.
Solution Approach 2:
The patent introduces a cleaning solution intermediary that flows through the valve body to reach and clean the gasket in-place. This intermediary cleaning medium enables effective cleaning without requiring physical removal of the gasket, thus maintaining production continuity while achieving thorough cleaning.
3Device complexity
If a single seal is used, then device complexity is reduced, but sealing reliability and leakage detection capability are insufficient
Solution Approach 1:
The patent segments the sealing function into two separate sealing surfaces on the gasket, creating a double seal arrangement. This segmentation provides both sealing reliability and leakage detection capability while maintaining relatively simple device structure. The first seal prevents leakage from the process side, and the second seal provides backup protection and enables leakage detection in the intermediate chamber.
Solution Approach 2:
The patent adds a spatial dimension to the sealing system by creating an intermediate chamber between two sealing surfaces. This dimensional addition allows for leakage detection functionality without significantly increasing overall device complexity, as the second seal and intermediate chamber are integrated into the existing valve body structure.
4Object-affected harmful factors
If PTFE gaskets are used, then chemical resistance is improved, but cleaning fluid circulation around the gasket is restricted
Solution Approach 1:
The patent employs a flexible PFA gasket that can dynamically adjust its position and shape to allow cleaning fluid circulation. The dynamic flexibility of the gasket enables cleaning solutions to flow around and contact all surfaces of the gasket effectively, while the material maintains its chemical resistance properties. This resolves the contradiction by providing both chemical resistance and ease of cleaning through the gasket's dynamic response to cleaning fluid flow.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Facilitates automatic and hygienic cleaning, enhances sealing capacity, detects leaks, and prevents contamination by allowing fluid circulation around the gasket during cleaning, while maintaining sealing integrity and reducing the risk of bacterial growth.
Implementation Method 1
upon dilating of the gasket when the valve stem-plug is in a non-sealing condition, the floating seal gasket it allows for circulation of cleaning fluid around all sides of the gasket
Implementation Method 2
the segments are arranged for sealing against a valve seat and thereby forming an double-contact seal
Implementation Method 3
the outer surface of the floating seal is concave between the upper and lower circumferentially extending segments such that a leakage chamber is formed between the valve seat and the upper and lower circumferentially extending segments
Data Source
AI summary
A valve stem-plug and seal assembly (1) comprising a valve stem-plug (2) having a first (3) and second (4) axially spaced peripheral shoulders forming a groove (5) there between. A floating seal gasket (6) is arranged in said groove (5). The floating seal gasket (6) is an annular ring with a central opening (7) through which the valve stem-plug (2) extends. Further, the outer surface (8) of the floating seal gasket (6) comprises an upper (9) and a lower (10) circumferential extending segment, wherein said segments are arranged for sealing against a valve seat (11) and thereby forming a double-contact seal. The outer surface (8) of the floating seal is concave between said upper and lower circumferentially extending segments (9,10) such that a leakage chamber (12) is formed between the valve seat (11) and said upper and lower circumferentially extending segments (9,10) when said double-contact seal is formed.